Fountain-pen.



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Patented oct. 3, |899.

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y UNITED mSTATES YPATELVI OFFICE.

OLIVER R. MITCHELL, OE BOSTON, MASSACHUSETTS, ASSIGNOR To RHODES LOcKwOoD, OF SAME PLACE.

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vFOUNTAIN-PEN.

SPECIFICATION forming part of Letters Patent No. 634,013, 4dated*October 3, 1899. Application ned umh 13,1899. 'semi H0. 708,851. No moda.)

it in place upon the end of a fountain-pen.

Fig. 2 is an end View of the cap, looking into the open end. Fig. 3 shows another embodi-` ment of my invention. Fig. 4 shows yet another embodiment of my invention. Fig. 5 is an end View of Fig. et, looking in .the direction of the arrow. v

My invention is an ink-joint for closing the open or pen end of fountain-pens to prevent the escape of ink when the pen is not in use.

In fountain-pens as heretofore made the vcap has been formed inv one of three Ways.

Either it has been a hollow cylinder closed at one end and adapted at its open endor mouth to tit upon the cylindrical end of the pointsection of the fountain-pen, or the Vcap has been formed as a hollow cone and used in connection With a conical point-section, `or the cap has been formed as a hollow cylinder, the inside of the mouth of which has been formed as a truncated cone, this form of cap-mouth being used in connection with a conical pointsection. The first and third forms of cap above mentioned were objectionable .in this that within the limits possible to be given for the engagement between cap and point-section it was not possible owing to the elastic nature of the material (hard rubber) of which caps are commonly made and owing to the necessary thinness of the walls of the cap to obtain a connection so firm and secure that .it was not liable to be disturbed and disconnected by the natural working of the cap upon the point-section under the influence of the leverage due to the length of the )free end of thecap. Furthermore, a diii'icultyv ical inside is that in the hands of ignorant yor inexperienced persons the cap-is likely to be forced upon the conical pen end so far and so hard as to split the cap and thus ruin it.

My improvement is designed to remedyV these difficulties by providing a cap different in its interior form and its manner of application tothe fountain-pen to anything heretofore known and more cheaply and easily made.

In the drawings, Fig. l shows the capAin longitudinal section formed as to its exterior in the common fashion as a'cylinder of univform size throughoutV its lenth, but as to its interior formed asv a hollow cylinder of two diameters, the part a. of largest diameter being that forming the mouth of the cap, the cylinder of Smaller diameter a forming the interior end. The diameter of the part a. is governed by the diameter of the cylindrical portion of the fountain-pen Bf-that is, that portion of the pen above the point b whereit begins to taper to the' pen-point and is designed to be a tight driving t for this portion of thepen. The open end of the inner portion Ct' is designed to pass Aup over the tai pered end ofthe pen-point and engage that tapered end when the open end a of the cap has passed upon the cylindrical lower end of the fountain-pen to the desired distance. The result of this construction is that an ink* tight joint is formed between the inner surface of the mouth a of the cap and the Vouter surface of the fountain-pen B,while the shoulder formed by the abrupt change from one interior cylindrical portion a to the other cylindrical portion a of the cap engaging the tapered end of fountain-pen serves as a support against sidewise strains and gives assecure a connection to the cap with the fountain-pen as Vifthe inner surface of the cap were in lcontact with the outer surface of the cylindrical portion of the fountain-pen from the mouth of the cap to the mouth of the inner cylindrical portion a" of the cap, at the same time leaving onlya minimum length of the outer end of the cap unsupported to act as a lever to Work the cap free from its engagement with the fountain-pen. ons that such a length of engagementbetween cap and fountain-pen asis in this manner provided for would be as a practical mat- It is obvi- IOO ter impossible in any other way, for a cap of such length as to pass upon the cylindrical portion of the `fountain-pen to such an extent would be so long as to be objectionable; Furthermore, even if this were not so the cap supposed, being unsupported from the beginning of the taper instead of from a point near the small end of thetaper, would exercise a much greater effect by way of leverage, tending to disconnect the two parts and to strain and distort the mouth of the outer cylindrical portion ce of the cap.

The inner cylindrical portion cd of the cap is of such a size as to receive the pen C and is vented by a small aperture a2, as is customary. l

The practical result that I have described above as arising from the construction illustrated in Fig. l may also be obtained by inserting into a hollow cylindrical cap whose interior diameter is uniform a ring a3 of hard rubber or the like and securing it in place, (see Fig. or the result may be obtained by forming three ormore knobs CL4 of suitable size at the proper place upon the interior surface of the cap to engage the tapered end of the fountain-pen and prevent sidewise movement of the cap. (See Fig. 4.)

What I claim iswithin and of equal interior diameter with the outer diameter of the barrel; a tapered pointsection at one end of the barrel and a projection within the cap adapted to engage the tapered point-section and to cooperate therewith, all organized and operating to form an ink-joint between the cylindrical portion of the barrel and the interior cylindrical mouth of the cap and a stop between the projection within the cap and the exterior of the tapered point-section, to regulate the extent of the ink-joint and secure the cap in position.

OLIVER R. MITCHELL.

Vitnesses:

EvERET'r E. KENT, JOSEPH T. BRENNAN. 

